1. Field of the Invention
The present invention relates to a treating method for imparting hydrophilicity or hydrophobicity to a solid surface, which is useful for forming images in a printing technique, for forming fine patterns in the field of electronic ceramics or for antifogging or antifouling technique for the surfaces of various articles. Particularly, it relates to the method for rapidly imparting hydrophobicity to the entire region or an optional local region of a hydrophilicity-imparted oxide solid surface.
2. Discussion of Background
It is known that when ultraviolet rays are irradiated to a solid surface such as a titanium oxide layer coated on the surface of various articles, the titanium oxide layer surface which has been hydrophobic, will be changed to be hydrophilic, and the contact angle of water to the surface will be not more than about 5xc2x0. By utilizing this phenomenon, a coating film composed essentially of titanium oxide may be formed on the surface of various articles to make the surface hydrophilic for the purpose of antifogging or antifouling. On the other hand, in an image-forming system in e.g. printing, a method of locally modifying a hydrophilic surface to be hydrophobic, to form a hydrophilic/hydrophobic image, has been known (JP-B-5-30273, JP-A-11-58831, etc.), or in the field of electronic ceramics, a method of employing partial hydrophobic treatment at the time of forming laminated patterns, has been known (JP-A-5-97407).
Heretofore, it used to take a few weeks by means of a dark storage process to return the surface having hydrophilicity once imparted by e.g. ultraviolet ray irradiation to a surface having the initial hydrophobic property. Further, such a dark storage process is a method of waiting until the sample surface will spontaneously regain the hydrophobicity, and it has been impossible to thereby change only an optional region of the sample surface to be hydrophobic, while maintaining other regions to be hydrophilic.
It is an object of the present invention to develop a technique whereby the time required to change the surface of inorganic material from hydrophilic to hydrophobic, can be shortened from a conventional few weeks to a level of a few tens of seconds, and an optional local position of the surface of the material can be selectively so changed. Such a technique is expected to be applied to e.g. a printing technique and an antifogging or antifouling technique.
The present inventors have found it possible to rapidly impart hydrophobicity to an optional region of a hydrophilicity-imparted oxide solid surface by locally exerting a mechanical stimulation to the optional region which is desired to be changed to be hydrophobic. The present invention has been accomplished on the bases of this discovery.
That is, the present invention provides a method for rapidly imparting hydrophobicity to an oxide solid surface, which comprises exerting a mechanical stimulation to a desired region of a hydrophilicity-imparted oxide solid surface, to change said region to be hydrophobic.
Further, the present invention provides such a method for rapidly imparting hydrophobicity to an oxide solid surface, wherein the mechanical stimulation is exerted while moisture is supplemented to the desired region of the oxide solid surface.
Still further, the present invention provides such a method for rapidly imparting hydrophobicity to an oxide solid surface, wherein the oxide is an oxide containing a titanium atom.
Furthermore, the present invention provides such a method for rapidly imparting hydrophobicity to an oxide solid surface, wherein the oxide containing a titanium atom is titanium dioxide having a crystal structure of anatase type or a rutile type, or a mixture of anatase and rutile types.